1. Field of the Invention
The present invention relates generally to a suspension control system for an automotive vehicle. More particularly, the invention is directed to modify damping coefficients of shock absorbers for suppressing rolling motion in transient turning, for example, when a vehicle enters a corner or approaches an end of the corner, securing good driving comfort.
2. Description of the Prior Art
Japanese Utility Model First Publication No. 59-117510 discloses an anti-rolling control system for an automotive vehicle. This control system is responsive to a sensor signal from a lateral acceleration sensor which detects lateral acceleration acting on a vehicle body to increase damping forces of shock absorbers or spring constants of air springs for suppressing rolling motion.
However, such a prior art suspension control system encounters a drawback in that the system is also responsive to lateral acceleration caused by vehicle attitude change created when a vehicle travels on an inclined road surface or is in steady circle turning. This causes transmissibility of vibration of an unsprung mass to a vehicle body to be undesirably increased, resulting in unpleasant riding comfort. In other words, modification of damping coefficients of shock absorbers does not serve to regulate vehicle attitude change due to inclination of a road surface. Additionally, during steady turning, a vehicle body remains inclined once a vehicle body is rolled. Therefore, even if damping coefficients of the shock absorber are modified during steady turning, the vehicle attitude change is not suppressed. In other words, the adjustment of damping coefficients of shock absorbers after transient rolling motion does not serve to control vehicle attitude change. Accordingly, it is desirable to perform damping force control of a shock absorber when the vehicle is in transient turning for suppressing sudden attitude change caused by rolling motion.